Friday, September 10, 2010

Ringtail Lemurs and Ultrarunning

I just read a wonderful, marvelous book: from Richard Dawkins, The Greatest Show on Earth--The Evidence for Evolution, Free Press, New York, New York, 2009. I laughed out loud at the part where he talks about geographic distribution of animals as being some of the most solid evidence for evolution.

Not laughing in derision, but more like “Right ON! You nailed it!” Specifically he was talking about how certain animals are found only in certain places on earth:

It is almost too ridiculous to mention it, but I'm afraid I have to because of the more than 40 per cent of the American population who, as I lamented in Chapter 1, accept the Bible literally: think what the geographical distribution of animals should look like if they'd all dispersed from Noah's Ark. Shouldn't there be some sort of law of decreasing species diversity as we move away from an epicenter - perhaps Mount Ararat? I don't need to tell you that that is not what we see.

Why would all those marsupials - ranging from tiny pouched mice through koalas and bilbys to giant kangaroos and Diprotodonts - why would all those marsupials, but no placentals at all, have migrated en masse from Mount Ararat to Australia? Which route did they take?

And why did not a single member of their straggling caravan pause on the way, and settle - in India, perhaps, or China, or some haven along the Great Silk Road? Why did the entire order Edentata (all twenty species of armadillo, including the extinct giant armadillo, all six species of sloth, including extinct giant sloths, and all four species of anteater) troop off unerringly for South America, leaving not a rack behind, leaving no hide nor hair nor armour plate of settlers somewhere along the way?

But when Hawkins goes on to focus specifically on lemurs and how they are only found in Madagascar, I blew coffee out my nose over the mental picture of a lemur hightailing it:

An ancestral lemur, again very possibly just a single species, found itself in Madagascar. Now there are thirty-seven species of lemur (plus some extinct ones). They range in size from the pygmy mouse lemur, smaller than a hamster, to a giant lemur, larger than a gorilla and resembling a bear, which went extinct quite recently. And they are all, every last one of them, in Madagascar. There are no lemurs anywhere else in the world, and there are no monkeys in Madagascar…Did all thirty-seven and more species of lemur troop in a body down Noah's gangplank and hightail it (literally in the case of the ringtail) for Madagascar, leaving not a single straggler by the wayside, anywhere throughout the length and breadth of Africa?

Then the nail in the coffin:

Even if we leave Mount Ararat to one side; even if we refrain from lampooning those who take the Noah's Ark myth literally, similar problems apply to any theory of the separate creation of species. Why would an all-powerful creator decide to plant his carefully crafted species on islands and continents in exactly the appropriate pattern to suggest, irresistibly, that they had evolved and dispersed from the site of their evolution?

The fact is that, if we survey every continent and every island, every lake and every river, every mountaintop and every Alpine valley, every forest and every desert, the only way to make sense of the distribution of animals and plants is, yet again, to follow Darwin's insight about the Galapagos finches: 'One might really fancy that from an original paucity ... one species had been taken and modified for different ends.'

I remember reading somewhere that the canids (dog family) and humans are the only trotting carnivores ever to evolve on the planet. I’m really happy that this set us up to enjoy Ultrarunning.